Cambodia's Prime Minister has a dozen senior army officials who commit serious human rights abuses on his behalf, a rights group claims

Senior members of Cambodia's security forces have committed human rights abuses that benefited Prime Minister Hun Sen, according to a report by Human Rights Watch.

The report describes alleged abuses committed by 12 police and army generals, who are also long-standing members of the Central Committee of Hun Sen's Cambodian People's Party.

Cambodians go to the polls on Friday and Hun Sen, who has ruled Cambodia for 33 years, is trying to ensure victory.

PHNOM PENH (Reuters) - Senior members of Cambodia's security forces have committed human rights abuses that benefited Prime Minister Hun Sen, including a crackdown on the opposition ahead of elections next month, Human Rights Watch (HRW) said on Thursday.

The group's latest report describes alleged abuses committed by 12 police and army generals, who are also long-standing members of the Central Committee of Hun Sen's Cambodian People's Party (CPP).

"Most of the 12 have been implicated in the use of unnecessary, excessive, and sometimes lethal force against protests about unfree and unfair elections, land confiscations, labor abuses, and low wages," the group said in the report.

"Many have also been involved in non-political abuses against the ordinary population, such as land takings, murder, torture, and arbitrary detention," it said.

The 12 generals named in the report included National Police Chief Neth Savoeun and Pol Saroeun, commander in chief of the military. They owed their "lucrative position to political and personal connections with Hun Sen dating back two decades or more", the group said.

Reuters was not able to contact either Neth Savoeun or Pol Saroeun.

The Ministry of Interior, which is responsible for the police, rejected the allegations in the report.

"Human Rights Watch is a professional liar," said Huy Vannak, undersecretary of state at the ministry.

"The report is too dramatic and it reflects a criminal intent of HRW to continue to downgrade Cambodia," he said.

Defense ministry spokesman Chhum Socheat said the report was unfair.

"On behalf of the Ministry of National Defense, we dismiss this report which lacks evidence," he said.

Human Rights Watch said the report was based on interviews with sources, media reports and documents. It did not give more details of how it obtained its findings or reached its conclusions.

Brad Adams, Asia director of Human Rights Watch, said Hun Sen has "created and developed a core of security force officers who have ruthlessly and violently carried out his orders".

"The importance of Cambodia's generals has become even more apparent ahead of July's elections, as they engage in crackdowns against journalists, political opponents, and anti-government protesters - and openly campaign for Hun Sen," Adams said in a statement accompanying the report.

Cambodians go to the polls on July 29 and Hun Sen, who has ruled Cambodia for 33 years, is trying to ensure victory after two close elections in 2013 and 2017 with a series of measures against the opposition.

Kem Sokha, the leader of the main opposition Cambodia National Rescue Party (CNRP) was arrested in September for alleged treason and the CNRP was dissolved in November at the government's request.